Preparation method of antiviral drug amonevir
By using a microfluidic reactor and high-performance liquid chromatography for separation and purification, the problems of high material cost and high purification difficulty in the synthesis of amonexvir were solved, and efficient and low-cost amonexvir production was achieved.
Patent Information
- Application Number
- CN202511436831.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-10-09
- Publication Date
- 2026-01-16
AI Technical Summary
Existing amonexvir synthesis routes suffer from high material costs, difficult purification, and difficulty in scaling up production. Existing technical routes also suffer from numerous byproducts and low yields.
Amonevir was purified by a microfluidic reactor via a nucleophilic substitution reaction of cyclopentane-4-formyl chloride sulfide with 2,6-dimethylaniline, followed by reaction with bromoacetic acid in the presence of potassium tert-butoxide, then condensation reaction with 4-(1,2,4-oxadiazol-3-yl)aniline and 1-hydroxybenzotriazole, and finally oxidation of the intermediate with hydrogen peroxide followed by separation and purification by high performance liquid chromatography.
The reaction process has been simplified, production costs have been reduced, reaction efficiency has been improved, and the product purity has reached 99.9%, which meets the requirements of green and modern production and is suitable for industrial-scale production.
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Figure CN121342814A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of pharmaceutical chemical synthesis technology, and in particular to a method for preparing the antiviral drug amonexvir. Background Technology
[0002] Herpesviruses are a class of enveloped DNA viruses that can infect humans and various animals, causing a wide range of clinical symptoms, from mild, self-limiting illness to life-threatening severe infections. These viruses can establish lifelong latent infection and relapse periodically, making them important pathogens in the field of infectious diseases.
[0003] Amenamevir, chemically named N-(2,6-dimethylphenyl)-N-(2-{[4-(1,2,4-oxadiazol-3-yl)phenyl]amino}-2-oxoethyl)-1,1-dioxothiophene-4-carboxamide, was initially developed by Astellas Pharma Inc., in collaboration with Maruho Co., Ltd. It was first approved in Japan in 2017 for the treatment of herpes zoster and in 2023 was approved for self-treatment of herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2) infections. As a non-nucleoside helicase-primase complex inhibitor, amenamevir exhibits superior pharmacokinetic properties compared to existing drugs such as acyclovir and valacyclovir.
[0004] Currently, there are relatively few publicly known synthetic routes for amonexil, which mainly include the following: Kontani et al. first reported a process for preparing amonexir in 2005. This method involves alkylation of aniline with ethyl bromoethyl, followed by amidation with a synthesized acyl chloride intermediate in a pyridine environment, and then saponification followed by condensation with aniline to obtain amonexir. However, this synthetic route suffers from several drawbacks, including the tendency for over-substitution of aniline with ethyl bromoethyl, resulting in dialkylation byproducts; low yield in the amide condensation step; and the potential for ester hydrolysis and other byproducts, leading to increased material costs. Therefore, this process is unsuitable for large-scale industrial production.
[0005] Building upon the work of Kontani et al., Zhang Xumeng et al. proposed an improved synthetic strategy. First, aniline and an acyl chloride intermediate are reacted via nucleophilic substitution to obtain an amide intermediate, which is then successively subjected to N-alkylation, ester hydrolysis, and amidation reactions to yield amonevir. However, this synthetic route suffers from the problem that the amide condensation reaction still occurs under alkaline conditions, easily leading to side reactions such as ester hydrolysis, resulting in difficult product purification and low yield. Therefore, it is also unsuitable for large-scale industrial production.
[0006] In 2020, Dömling et al. synthesized amonexvir via a Ugi four-component one-pot reaction. The process involved adding triethylamine to a dichloromethane solution of N-(4-(1,2,4-oxadiazol-3-yl)phenyl)carboxamide, followed by the slow dropwise addition of triphosgene, and stirring at 0°C for 20 minutes. Subsequently, paraformaldehyde, 2,6-dimethylaniline, tetrahydro-2H-thiopyran-4-carboxylic acid-1,1-dioxide, and methanol were added sequentially, and the reaction was continued for 48 hours. After the reaction, the solvent was concentrated under reduced pressure, and the residue was purified by rapid chromatography to obtain the amonexvir product. However, the final product under this synthetic route still requires purification by silica gel column chromatography, and the one-pot reaction time is relatively long, which is not conducive to improving the utilization efficiency of the reaction vessel during production. Therefore, this route is still difficult to apply to large-scale industrial production.
[0007] Therefore, given the problems of high cost of amonexil synthesis materials, difficulty in purification, and difficulty in large-scale production in existing technologies, there is an urgent need to develop a low-cost amonexil preparation process suitable for industrial-scale production. Summary of the Invention
[0008] The purpose of this invention is to provide a method for preparing the antiviral drug amonexvir, so as to solve the problems of the existing amonexvir synthesis route being unable to be scaled up for production, high material costs, and difficulty in purification.
[0009] To address the above problems, this invention provides a method for preparing the antiviral drug amonexvir, comprising the following preparation process: S1. Cyclopentane-4-formyl chloride sulfide and 2,6-dimethylaniline are dissolved in solvents and then pumped into the first reactor to react, yielding reaction solution A; S2. Dissolve potassium tert-butoxide and bromoacetic acid separately in solvents and then pump them into the second reactor with reaction solution A to react and obtain reaction solution B; S3. Dissolve 4-(1,2,4-oxadiazol-3-yl)aniline and 1-hydroxybenzotriazole in a solvent, dissolve 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride in a solvent, and then pump the reaction solution B into the third reactor to react and obtain reaction solution C. S4. A mixed solution of acetonitrile with a hydrogen peroxide concentration of 0.5-2.0 mol / L and reaction solution C are pumped into the fourth reactor to react and obtain crude amonexil. After purification, amonexil is obtained. S5. The configuration and purity of amonexvir were analyzed by high performance liquid chromatography.
[0010] By adopting the above technical solution, the specific process for synthesizing amonexvir in this invention is as follows: First, a nucleophilic substitution reaction is carried out between cyclopentane-4-formyl chloride sulfide and 2,6-dimethylaniline to obtain reaction solution A, wherein reaction solution A is a solution containing intermediate 3, and the reaction process is as follows:
[0011] Subsequently, under the condition of potassium tert-butoxide as a base, intermediate 3 undergoes a nucleophilic substitution reaction with bromoacetic acid to obtain reaction solution B, which is a solution containing intermediate 5. The reaction process is shown below:
[0012] Next, the carboxyl group of intermediate 5 and the amino group of 4-(1,2,4-oxadiazol-3-yl)aniline undergo dehydration condensation in the presence of condensing agents 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDCI) and 1-hydroxybenzotriazole (HOBt) to obtain reaction solution C, which is a solution containing intermediate 7. The reaction process is shown below:
[0013] Subsequently, the thioether structure in intermediate 7 was converted to sulfone under hydrogen peroxide oxidation to obtain crude amonexvir. The reaction process is shown below: .
[0014] In the synthesis of amonexvir, the spatial rotation of the amide bond is hindered, resulting in two configurations of amonexvir. High performance liquid chromatography (HPLC) can be used to analyze the configurations and calculate the purity of amonexvir.
[0015] Preferably, amonex exists in two configurations: Z-type and E-type. The structural formulas of the two configurations of amonex are as follows: .
[0016] Preferably, the solvent includes anhydrous tetrahydrofuran, acetonitrile, and N,N-dimethylformamide.
[0017] Preferably, the preparation method of cyclopentane-4-formyl chloride sulfide includes the following steps: Tetrahydrothiaran-4-carboxylic acid is dissolved in dichloromethane, thionyl chloride is added, and the mixture is reacted at 10–30 °C for 1–4 h to obtain the product.
[0018] Preferably, the molar ratio of tetrahydrothiaran-4-carboxylic acid to thionyl chloride is 1:(1.0-3).
[0019] Preferably, in step S1, the concentration of cyclopentane-4-formyl chloride sulfide is 0.25–1.0 mol / L; the concentration of 2,6-dimethylaniline is 0.25–1.0 mol / L.
[0020] More preferably, in step S1, the concentration of cyclopentane-4-formyl chloride sulfide is 0.5 mol / L; and the concentration of 2,6-dimethylaniline is 0.25–1.0 mol / L.
[0021] Preferably, in step S2, the concentration of potassium tert-butoxide is 0.38–1.5 mol / L; and the concentration of bromoacetic acid is 0.13–0.5 mol / L.
[0022] More preferably, in step S2, the concentration of potassium tert-butoxide is 0.75 mol / L and the concentration of bromoacetic acid is 0.25 mol / L.
[0023] Preferably, in step S3, the concentration of 4-(1,2,4-oxadiazol-3-yl)aniline is 37.5–150 mmol / L; the concentration of 1-hydroxybenzotriazole is 12.5–50 mmol / L; and the concentration of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride is 37.5–150 mmol / L.
[0024] More preferably, in step S3, the concentration of 4-(1,2,4-oxadiazol-3-yl)aniline is 75 mmol / L, the concentrations of 4-(1,2,4-oxadiazol-3-yl)aniline and 1-hydroxybenzotriazole are 25 mmol / L, and the concentration of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride is 75 mmol / L.
[0025] More preferably, in step S4, the concentration of hydrogen peroxide is 1 mol / L.
[0026] Preferably, in step S5, the high-performance liquid chromatography method includes the following steps: S501. A C18 column was used, with 0.1%–0.3% H3PO4-H2O as mobile phase A and acetonitrile as mobile phase B. The flow rate was 0.7–0.9 mL / min, the column temperature was 30–45 ℃, and the diluent volume ratio was 1:(1–1.5) in a mixed solution of acetonitrile and water. The detection wavelength was 215 nm. S502. A C18 column was used with 10–30 Mm KH2PO4 as mobile phase A and MeOH as mobile phase B. The flow rate was 1.0–3.0 mL / min, the column temperature was 20–40 ℃, and the diluent volume ratio was 1:(1–1.5) of a mixed solution of acetonitrile and water. The detection wavelength was 210 nm.
[0027] Preferably, the pumping rates of cyclopentane-4-formyl chloride sulfide and 2,6-dimethylaniline are all 1.0–5.0 mL / min; the pumping rates of potassium tert-butoxide, bromoacetic acid, and reaction solution A are all 1.2–5.5 mL / min; the pumping rates of 4-(1,2,4-oxadiazol-3-yl)aniline, 1-hydroxybenzotriazole, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, and reaction solution B are all 1.5–6.5 mL / min; and the pumping rates of the mixed solution of hydrogen peroxide and acetonitrile and reaction solution C are all 2.0–8.0 mL / min.
[0028] More preferably, the pumping rate of cyclopentane-4-carboxyl chloride sulfide and 2,6-dimethylaniline is 1.5 mL / min; the pumping rate of potassium tert-butoxide, bromoacetic acid and reaction solution A is 2.0 mL / min; the pumping rate of 4-(1,2,4-oxadiazol-3-yl)aniline, 1-hydroxybenzotriazole, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and reaction solution B is 3.0 mL / min; and the pumping rate of the mixed solution of hydrogen peroxide and acetonitrile and reaction solution C is 4.0 mL / min.
[0029] Preferably, the temperature of the first microchannel reactor is 5–30°C; the temperature of the second microchannel reactor is 10–20°C; the temperature of the third microchannel reactor is 50–70°C; and the temperature of the fourth microchannel reactor is 70–90°C.
[0030] More preferably, the temperature of the first microchannel reactor is 10°C; the temperature of the second microchannel reactor is 20°C; the temperature of the third microchannel reactor is 60°C; and the temperature of the fourth microchannel reactor is 80°C.
[0031] Preferably, the pressure of the first microchannel reactor is 1.0–3.0 MPa; the pressure of the second microchannel reactor is 1.0–3.0 MPa; the pressure of the third microchannel reactor is 1.5–4.0 MPa; and the pressure of the fourth microchannel reactor is 2.0–6.0 MPa.
[0032] More preferably, the pressure of the first microchannel reactor is 1.0 MPa; the pressure of the second microchannel reactor is 1.5 MPa; the pressure of the third microchannel reactor is 2 MPa; and the pressure of the fourth microchannel reactor is 3 MPa.
[0033] Preferably, in step S4, purification includes the following specific steps: After removing the organic solvent by vacuum distillation at 40–50 °C, crude amonexilant is extracted with 2–5 times the volume of dichloromethane of the residual aqueous phase. The organic phase is collected, and the dichloromethane is removed by vacuum distillation. The remaining solid is then dissolved by heating with 5–7 times its weight of ethanol to reflux. Stirring is stopped, and the mixture is allowed to cool naturally to crystallize, thus obtaining solid amonexilant.
[0034] More preferably, in step S4, purification includes the following specific steps: After removing the organic solvent by vacuum distillation at 40°C, the crude amonexilate was extracted with 3 times the volume of dichloromethane from the residual aqueous phase. The organic phase was collected, and the dichloromethane was removed by vacuum distillation. The remaining solid was dissolved by heating with 6 times its weight of ethanol to reflux. Stirring was stopped, and the mixture was allowed to cool naturally to crystallize, thus obtaining amonexil solid.
[0035] The beneficial effects of this invention are: 1. This invention provides a method for synthesizing the antiviral drug amonexvir using a microfluidic reactor, filling a gap in existing amonexvir synthesis technology. This method significantly simplifies the reaction process, effectively reduces production costs, significantly improves reaction efficiency, shortens reaction time, and yields amonexvir product with high purity, reaching 99.9% in liquid phase, meeting the requirements of green and modern production.
[0036] 2. The detection method for amonexil and its tautomers provided by this invention can easily and efficiently separate its tautomers, providing a reliable guarantee for the industrial production of amonexil. Attached Figure Description
[0037] Figure 1 This is a schematic diagram of the process for synthesizing the antiviral drug amonexvir using a microfluidic reactor according to the present invention; Figure 2 The proton nuclear magnetic resonance spectrum of amonexil prepared for this invention ( 1 H-NMR); Figure 3 The high-performance liquid chromatography (HPLC) chromatogram of amonexvir prepared in Example 1; Figure 4 List of peaks from the HPLC chromatogram of amonexvir prepared in Example 1; Figure 5 Here is the HPLC chromatogram of the amonexvir tautomers prepared in Example 1; Figure 6 A list of peaks from the HPLC chromatogram of the amonexvir tautomers prepared in Example 1; Figure 7 The HPLC chromatogram of amonexvir prepared in Example 2; Figure 8 List of peaks from the HPLC chromatogram of amonexvir prepared in Example 2; Figure 9 Here is the HPLC chromatogram of amonexvir prepared in Example 3; Figure 10 List of peaks from the HPLC chromatogram of amonexvir prepared in Example 3; Figure 11The HPLC chromatogram of amonexvir prepared as a comparative example; Figure 12 A list of peaks from the HPLC chromatogram of amonexvir prepared in comparison. Figure 13 This is a schematic diagram of the process for synthesizing the antiviral drug amonexvir using a traditional reactor apparatus according to the present invention; Figure 14 Comparative pharmacokinetic curves of amonexvir and acyclovir prepared for this invention in mice. Detailed Implementation
[0038] The specific embodiments of the present invention will be described in detail below, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments.
[0039] Preparation Example
[0040] Preparation Example 1, a sulfide cyclopentane-4-formyl chloride, includes the following steps: Dissolve 0.391 mol of tetrahydrothiaran-4-carboxylic acid in 200 mL of dichloromethane, add 0.782 mol of thionyl chloride, and incubate at 25 °C for 2 hours to obtain cyclopentane-4-carboxyl chloride sulfide.
[0041] Example
[0042] Example 1: A method for preparing the antiviral drug amonexvir, comprising the following steps: S1. 0.391 mol of cyclopentane-4-formyl chloride prepared in Preparation Example 1 was dissolved in 782 mL of anhydrous tetrahydrofuran, and 0.391 mol of 2,6-dimethylaniline was dissolved in 782 mL of anhydrous tetrahydrofuran. Both solutions were simultaneously pumped into the first microchannel reactor at the same rate of 1.5 mL / min to carry out the first amidation reaction. The temperature of the first microchannel reactor was 10 °C, and the pressure was 1 MPa. The resulting reaction solution A was obtained. Figure 1 A tetrahydrofuran solution of intermediate 3 in the mixture.
[0043] S2. Dissolve 1.173 mol of potassium tert-butoxide in 1.564 L of anhydrous tetrahydrofuran, and dissolve 0.391 mol of bromoacetic acid in 1.564 L of anhydrous tetrahydrofuran. Simultaneously pump reaction solution A, the potassium tert-butoxide solution, and the bromoacetic acid solution into a second microchannel reactor at the same rate of 2.0 mL / min for the second amidation reaction. The temperature of the second microchannel reactor is 20 °C, and the pressure is 1.5 MPa, yielding reaction solution B, i.e., [the following is incomplete and requires further context: "attached"] Figure 1 A tetrahydrofuran solution of intermediate 5 in the mixture.
[0044] S3. 0.352 mol of 4-(1,2,4-oxadiazol-3-yl)aniline and 0.117 mol of HOBt were dissolved in 4.7 L of anhydrous tetrahydrofuran. 0.352 mol of EDCI was also dissolved in 4.7 L of anhydrous tetrahydrofuran. Reaction solution B, the mixed solution of 4-(1,2,4-oxadiazol-3-yl)aniline and HOBt, and the EDCI solution were simultaneously pumped into a third microchannel reactor at the same rate of 3.0 mL / min for the third amidation reaction. The temperature of the third microchannel reactor was 60 °C and the pressure was 2.0 MPa, yielding reaction solution C, i.e., [the following is incomplete and requires further context: "Attached..."] Figure 1 A tetrahydrofuran solution of intermediate 7 in the mixture.
[0045] S4. Dissolve 3.52 mol of 35% hydrogen peroxide and 3.414 L of acetonitrile. Simultaneously pump this solution and reaction solution C into the fourth microchannel reactor at the same rate (4.0 mL / min) for oxidation. The temperature of the fourth microchannel reactor is 80℃ and the pressure is 3.0 MPa, yielding crude amonexilate. A schematic diagram of the microfluidic reactor for synthesizing the antiviral drug amonexilate is attached. Figure 1 .
[0046] After removing the organic solvent from the oxidized crude amonexilate by vacuum distillation at 40°C, 300 ml of dichloromethane was added for extraction. The organic phase was collected, and the dichloromethane was removed by vacuum distillation at 40°C. The remaining solid was dissolved by heating with 900 mL of anhydrous ethanol to reflux. After the solution was completely dissolved, stirring was stopped, heating was turned off, and the solution was allowed to cool naturally to 25°C to crystallize, yielding 110 g of white needle-like amonexilate solid. The solid was then dried in a forced-air oven at 45°C for 12 hours to obtain the antiviral drug amonexilate.
[0047] S501, using Agilent XDB-C18 50 A 3.0 mm 2.7 μm column was used with 0.1% H3PO4-H2O as mobile phase A and acetonitrile as mobile phase B, with a volume ratio of mobile phase B to mobile phase A of 30:70. The flow rate was 0.7 mL / min, the injection volume was 2 μL, the column temperature was 40 °C, and the diluent was a 1:1 mixture of acetonitrile and water. Detection was performed at a wavelength of 215 nm, followed by isocratic elution after 15 min. The HPLC chromatogram and peak list are shown below. Figure 3 and Figure 4 As shown; S502, using Agilent XDB-C18 150 A 4.6 mm 5 μm column was used with 10 Mm KH₂PO₄ as mobile phase A and MeOH as mobile phase B, with a volume ratio of mobile phase B to mobile phase A of 40:60. The flow rate was 1.0 mL / min, the injection volume was 5 μL, the column temperature was 35 °C, and the diluent was a 1:1 mixture of acetonitrile and water. Detection was performed at a wavelength of 210 nm, followed by isocratic elution after 30 min. The HPLC chromatogram and peak list are shown below. Figure 5 and Figure 6 As shown.
[0048] Depend on Figure 3 and Figure 4 It can be seen that the purity of amonexvir reached 99.9%, the overall yield of the four-step reaction was 58%, and the minimum content of a single impurity was less than 0.1%; Figure 5 and Figure 6 It can be seen that the peaks of amonexvir exhibit a "boat-shaped" peak shape, and the integrated area of each "boat-shaped" peak changes significantly with the injection concentration, column temperature, and mobile phase pH. This is because amonexvir exists in two conformations, Z and E, due to the hindered spatial rotation of the amide bond.
[0049] Example 2, a method for preparing the antiviral drug amonexvir, comprising the following steps: S1. 0.391 mol of cyclopentane-4-formyl chloride prepared in Preparation Example 1 was dissolved in 391 mL of anhydrous tetrahydrofuran, and 0.391 mol of 2,6-dimethylaniline was dissolved in 391 mL of anhydrous tetrahydrofuran. These solutions were simultaneously pumped into the first microchannel reactor at the same rate of 5.0 mL / min to carry out the first amidation reaction. The temperature of the first microchannel reactor was 30 °C, and the pressure was 3 MPa. The resulting reaction solution A was obtained. Figure 1 A tetrahydrofuran solution of intermediate 3 in the mixture.
[0050] S2. Dissolve 1.173 mol of potassium tert-butoxide in 782 mL of anhydrous tetrahydrofuran, and dissolve 0.391 mol of bromoacetic acid in 782 mL of anhydrous tetrahydrofuran. Simultaneously pump reaction solution A, the potassium tert-butoxide solution, and the bromoacetic acid solution into a second microchannel reactor at the same rate of 5.5 mL / min for the second amidation reaction. The temperature of the second microchannel reactor is 20℃, and the pressure is 3 MPa, yielding reaction solution B, i.e., [the following is incomplete and requires further context: "attached"] Figure 1 A tetrahydrofuran solution of intermediate 5 in the mixture.
[0051] S3. Dissolve 0.352 mol of 4-(1,2,4-oxadiazol-3-yl)aniline and 0.117 mol of HOBt in 2.35 L of anhydrous tetrahydrofuran, and dissolve 0.352 mol of EDCI in 2.35 L of anhydrous tetrahydrofuran. Simultaneously pump reaction solution B, the mixed solution of 4-(1,2,4-oxadiazol-3-yl)aniline and HOBt, and the EDCI solution into a third microchannel reactor at the same rate of 6.6 mL / min for the third amidation reaction. The temperature of the third microchannel reactor is 70 °C, and the pressure is 4.0 MPa, yielding reaction solution C, i.e., [the following is incomplete and requires further context: "Attached"] Figure 1 A tetrahydrofuran solution of intermediate 7 in the mixture.
[0052] S4. Dissolve 3.52 mol of 35% hydrogen peroxide and 1.654 L of acetonitrile. Simultaneously pump this solution and reaction solution C into the fourth microchannel reactor at the same rate (8.0 mL / min) for oxidation. The temperature of the fourth microchannel reactor is 90℃ and the pressure is 6.0 MPa, yielding crude amonexilate. A schematic diagram of the microfluidic reactor for synthesizing the antiviral drug amonexilate is attached. Figure 1 .
[0053] After removing the organic solvent from the oxidized crude amonexilate by vacuum distillation at 50°C, 500 mL of dichloromethane was added for extraction. The organic phase was collected, and the dichloromethane was removed by vacuum distillation at 40°C. The remaining solid was dissolved by heating with 1.05 L of anhydrous ethanol to reflux. After the solution was completely dissolved, stirring was stopped, heating was turned off, and the solution was allowed to cool naturally to 25°C to crystallize, yielding 83 g of white needle-like amonexilate solid. The solid was then dried in a forced-air oven at 45°C for 12 hours to obtain the antiviral drug amonexilate.
[0054] S501, using Agilent XDB-C18 50 A 3.0 mm 2.7 μm column was used with 0.1% H3PO4-H2O as mobile phase A and acetonitrile as mobile phase B, with a volume ratio of mobile phase B to mobile phase A of 30:70. The flow rate was 0.7 mL / min, the injection volume was 2 μL, the column temperature was 40 °C, and the diluent was a 1:1 mixture of acetonitrile and water. Detection was performed at a wavelength of 215 nm, followed by isocratic elution after 15 min. The HPLC chromatogram and peak list are shown below. Figure 7 and Figure 8 As shown; Depend on Figure 7 and Figure 8 It can be seen that the purity of amonexvir reached 98.4%, and the overall yield of the four-step reaction was 44%.
[0055] Example 3, a method for preparing the antiviral drug amonexvir, comprising the following steps: S1. 0.391 mol of cyclopentane-4-formyl chloride prepared in Preparation Example 1 was dissolved in 3.91 L of anhydrous tetrahydrofuran, and 0.391 mol of 2,6-dimethylaniline was dissolved in 782 mL of anhydrous tetrahydrofuran. These solutions were simultaneously pumped into the first microchannel reactor at the same rate of 1.0 mL / min to carry out the first amidation reaction. The temperature of the first microchannel reactor was 5 °C, and the pressure was 1 MPa. The resulting reaction solution A was obtained. Figure 1 A tetrahydrofuran solution of intermediate 3 in the mixture.
[0056] S2. Dissolve 1.173 mol of potassium tert-butoxide in 3.09 L of anhydrous tetrahydrofuran, and dissolve 0.391 mol of bromoacetic acid in 3.01 L of anhydrous tetrahydrofuran. Simultaneously pump reaction solution A, the potassium tert-butoxide solution, and the bromoacetic acid solution into a second microchannel reactor at the same rate of 2.0 mL / min for the second amidation reaction. The temperature of the second microchannel reactor is 20 °C, and the pressure is 1.5 MPa, yielding reaction solution B, i.e., [the following is incomplete and requires further context: "attached"] Figure 1 A tetrahydrofuran solution of intermediate 5 in the mixture.
[0057] S3. Dissolve 0.352 mol of 4-(1,2,4-oxadiazol-3-yl)aniline and 0.117 mol of HOBt in 9.39 L of anhydrous tetrahydrofuran, and dissolve 0.352 mol of EDCI in 9.39 L of anhydrous tetrahydrofuran. Simultaneously pump reaction solution B, the mixed solution of 4-(1,2,4-oxadiazol-3-yl)aniline and HOBt, and the EDCI solution into a third microchannel reactor at the same rate of 1.5 mL / min for the third amidation reaction. The temperature of the third microchannel reactor is 50 °C, and the pressure is 1.5 MPa, yielding reaction solution C, i.e., [the following is incomplete and requires further context: "Attached"] Figure 1 A tetrahydrofuran solution of intermediate 7 in the mixture.
[0058] S4. Dissolve 3.52 mol of 35% hydrogen peroxide in 6.934 L of acetonitrile. Simultaneously pump this solution and reaction solution C into the fourth microchannel reactor at the same rate (2.0 mL / min) for oxidation. The temperature of the fourth microchannel reactor is 70 °C and the pressure is 2.0 MPa, yielding crude amonexilate. A schematic diagram of the microfluidic reactor for synthesizing the antiviral drug amonexilate is attached. Figure 1 .
[0059] After removing the organic solvent from the oxidized crude amonexilate by vacuum distillation at 40°C, 300 mL of dichloromethane was added for extraction. The organic phase was collected, and the dichloromethane was removed by vacuum distillation at 40°C. The remaining solid was dissolved by heating with 900 mL of anhydrous ethanol to reflux. After the solution was completely dissolved, stirring was stopped, heating was turned off, and the solution was allowed to cool naturally to 25°C to crystallize, yielding 110 g of white needle-like amonexilate solid. The solid was then dried in a forced-air oven at 45°C for 12 hours to obtain the antiviral drug amonexilate.
[0060] S501, using Agilent XDB-C18 50 A 3.0 mm 2.7 μm column was used with 0.1% H3PO4-H2O as mobile phase A and acetonitrile as mobile phase B, with a volume ratio of mobile phase B to mobile phase A of 30:70. The flow rate was 0.7 mL / min, the injection volume was 2 μL, the column temperature was 40 °C, and the diluent was a 1:1 mixture of acetonitrile and water. Detection was performed at a wavelength of 215 nm, followed by isocratic elution after 15 min. The HPLC chromatogram and peak list are shown below. Figure 9 and Figure 10 As shown; Depend on Figure 9 and Figure 10 It can be seen that the purity of amonexvir reached 98.5%, and the overall yield of the four-step reaction was 41%.
[0061] Comparative Example
[0062] Comparative Example 1: A method for preparing the antiviral drug amonexvir, comprising the following steps: 0.391 mol of cyclopentane-4-formyl chloride prepared in Preparation Example 1 was dissolved in 782 mL of anhydrous tetrahydrofuran, and 0.391 mol of 2,6-dimethylaniline was dissolved in 782 mL of anhydrous tetrahydrofuran. The mixture was added to a conventional reaction vessel and reacted at 30 °C for 2 hours to complete the first amidation reaction.
[0063] Then, 1.173 mol of potassium tert-butoxide was dissolved in 1.564 L of anhydrous tetrahydrofuran, and 0.391 mol of bromoacetic acid was dissolved in 1.564 L of anhydrous tetrahydrofuran. These were added sequentially to the reactor and reacted at 20°C for 24 hours. The control panel detected that 15% of intermediate 3 remained. The reaction was extended to 36 hours, and 12% of intermediate 3 remained.
[0064] Then, 0.352 mol of 4-(1,2,4-oxadiazol-3-yl)aniline and 0.117 mol of HOBt were dissolved in 4.7 L of anhydrous tetrahydrofuran and added to the reactor. 0.352 mol of EDCI was dissolved in 4.7 L of anhydrous tetrahydrofuran and added to the reactor. The mixture was heated to 60 °C and reacted for 12 hours to complete the third amidation reaction.
[0065] Finally, a mixed solution of 3.52 mol 35% hydrogen peroxide and 3.414 L acetonitrile was added to the reactor, the temperature was raised to 80°C, and the reaction was carried out for 72 hours. A schematic diagram of the process for synthesizing the antiviral drug amonexvir using a conventional reactor apparatus is attached. Figure 8 .
[0066] After the reaction was completed, 5% of the sulfoxide intermediate could not be converted into sulfone. After concentration under reduced pressure at 40°C to remove the organic solvent, 300 mL of dichloromethane was added for extraction. The organic phase was collected, and after distillation under reduced pressure at 40°C to remove the dichloromethane, the remaining solid was dissolved by heating with 900 mL of anhydrous ethanol to reflux. After the solution was completely dissolved, stirring was stopped, heating was turned off, and the solution was allowed to cool naturally to 25°C to crystallize, yielding 38 g of solid, which is an antiviral drug, amonexvir.
[0067] Agilent XDB-C18 50 A 3.0 mm 2.7 μm column was used with 0.1% H3PO4-H2O as mobile phase A and acetonitrile as mobile phase B, with a volume ratio of mobile phase B to mobile phase A of 30:70. The flow rate was 0.7 mL / min, the injection volume was 2 μL, the column temperature was 40 °C, and the diluent was a 1:1 mixture of acetonitrile and water. Detection was performed at a wavelength of 215 nm, followed by isocratic elution after 15 min. The HPLC chromatogram and peak list are shown below. Figure 11 and Figure 12 As shown; Depend on Figure 11 and Figure 12 It can be seen that the purity of amonexvir is 82.8%, and the overall yield of the four-step reaction is only 17%.
[0068] Performance testing
[0069] 1. 1 H-NMR detection: The purified amonexvir from Example 1 was analyzed... 1 H-NMR detection, spectrum as shown in Figure 2 As shown; 2. Purity and Yield Detection: The purity and overall yield of Examples 1-3 and Comparative Example 1 were calculated using HPLC; the results are shown in Table 1. 3. Pharmacokinetic Tests: For pharmacokinetic analysis, BALB / c mice (n=7 per group) were divided into 3 groups. Each group of mice was injected via tail vein with one of the following drug solutions, each at a concentration of 7 μM, dissolved in 200 μL PBS solution: (1) blank control group, (2) amonexvir test group prepared in Example 1, and (3) acyclovir (CAS: 59277-89-3) control group. Blood samples were collected from the submandibular vein at predetermined time points (0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, and 12 hours after injection). The samples were centrifuged at 20,000 rpm for 10 minutes to obtain plasma. The concentration change of perbiprofen salt in plasma was determined by HPLC, and the relationship curve of blood drug concentration versus time was plotted based on the ratio of the peak area of each sample to the peak area at 0. The pharmacokinetic test results are as follows. Figure 8 As shown.
[0070] Table 1. Calculation results of purity and yield
[0071] from Figure 2 It is known that the substance synthesized in this invention is amonevir, and the specific peaks are as follows: 1H NMR (400 MHz, CDCl3) δ 9.43 (s, 1H), 8.74 (s, 1H), 8.19-7.95 (m,2H), 7.76-7.58 (m, 2H), 7.23 (dd, J = 8.5, 6.4 Hz, 1H), 7.19-7.12 (m, 2H), 4.27 (s, 2H), 3.40-3.23 (m, 2H), 2.86-2.69 (m, 2H), 2.43-2.29 (m, 3H), 2.22 (s, 6H), 2.12-2.01 (m, 2H).
[0072] Combining Table 1 and Figure 3 , Figure 4 and Figures 7-12 As can be seen from this, the purity of amonex prepared by this invention can reach 99.9%, and the total yield can reach 58%; while the purity of amonex prepared in the comparative example is only 82.8%, and the total yield is only 17%.
[0073] from Figure 8 It can be seen that the amonexvir prepared in Example 1 of this invention is metabolized and cleared more slowly in mice than acyclovir, which indicates that amonexvir can exert its antiviral function for a longer period of time.
[0074] The results above show that the method for synthesizing the antiviral drug amonexvir based on a microfluidic reactor provided by this invention can significantly improve reaction efficiency. Compared with the traditional batch synthesis method, this method not only significantly improves the yield and reduces the amount of by-products, but also yields amonexvir products with higher purity.
[0075] The above-disclosed embodiments are merely a few specific examples of the present invention. However, the embodiments of the present invention are not limited thereto, and any variations that can be conceived by those skilled in the art should fall within the protection scope of the present invention.
Claims
1. A process for the preparation of the antiviral drug amodiaquine, characterized in that, The reaction process comprises the following steps: S1, sulfide cyclopentane-4-formyl chloride and 2,6-dimethylaniline are dissolved in solvents respectively and then pumped into a first micro-channel reactor to react to obtain reaction liquid A; S2, potassium tert-butoxide and bromoacetic acid are dissolved in solvents respectively and then pumped into a second micro-channel reactor with reaction liquid A to react to obtain reaction liquid B; S3, 4-(1,2,4-oxadiazol-3-yl) aniline and 1-hydroxybenzotriazole are dissolved in solvents, and 1-(3-dimethylaminopropyl)-3-ethyl carbodiimide hydrochloride is dissolved in solvents, and then pumped into a third micro-channel reactor with reaction liquid B to react to obtain reaction liquid C; S4, a mixed solution of hydrogen peroxide with a concentration of 0.5-2.0 mol / L in acetonitrile and reaction liquid C are pumped into a fourth micro-channel reactor to react to obtain an amonevir crude product effluent, which is purified to obtain amonevir; S5, high performance liquid chromatography is used to analyze the configuration and purity of amonevir.
2. A process for the preparation of antiviral drug Amoynivir as claimed in claim 1, wherein, The amonevir configuration has two configurations of Z type and E type, and the structural formula of the two configurations of amonevir is as follows: 。 3. A process for the preparation of antiviral drug Amoynivir as claimed in claim 1, wherein, The preparation method of the sulfide cyclopentane-4-formyl chloride comprises the following steps: Tetrahydrothiopyran-4-carboxylic acid is dissolved in dichloromethane, and thionyl chloride is added, and then reacted at 10-30℃ for 1-4 hours to obtain the sulfide cyclopentane-4-formyl chloride.
4. A process for the preparation of antiviral drug Amoynivir as claimed in claim 1, wherein, In step S1, the concentration of the sulfide cyclopentane-4-formyl chloride is 0.25-1.0 mol / L, and the concentration of the 2,6-dimethylaniline is 0.25-1.0 mol / L.
5. The process for the preparation of antiviral drug Amoanevir as claimed in claim 1 wherein, In step S2, the concentration of the potassium tert-butoxide is 0.38-1.5 mol / L, and the concentration of the bromoacetic acid is 0.13-0.5 mol / L.
6. The process for the preparation of antiviral drug Amoanevir as claimed in claim 1, wherein, In step S3, the concentration of the 4-(1,2,4-oxadiazol-3-yl) aniline is 37.5-150 mmol / L, the concentration of the 1-hydroxybenzotriazole is 12.5-50 mmol / L, and the concentration of the 1-(3-dimethylaminopropyl)-3-ethyl carbodiimide hydrochloride is 37.5-150 mmol / L.
7. The process for the preparation of antiviral drug Amoanevir as claimed in claim 1, wherein, In step S5, the high performance liquid chromatography comprises the following steps: S501, C18 chromatographic column is used, 0.1%-0.3% H3PO4-H2O is used as mobile phase A, acetonitrile is used as mobile phase B, the flow rate is 0.7-0.9 mL / min, the column temperature is 30-45℃, the diluent volume ratio is 1: (1-1.5) of a mixed solution of acetonitrile and water, and detection is performed at a detection wavelength of 215 nm; S502, C18 chromatographic column is used, 10-30 Mm KH2PO4 is used as mobile phase A, MeOH is used as mobile phase B, the flow rate is 1.0-3.0 mL / min, the column temperature is 20-40℃, the diluent volume ratio is 1: (1-1.5) of a mixed solution of acetonitrile and water, and detection is performed at a detection wavelength of 210 nm.
8. A process for the preparation of antiviral drug Amoynivir as claimed in claim 1, wherein, The pump-in rate of the sulfided cyclopentane-4-formyl chloride and 2,6-dimethylaniline is 1.0-5.0 mL / min; the pump-in rate of the potassium tert-butoxide, bromoacetic acid and reaction liquid A is 1.2-5.5 mL / min; the pump-in rate of the 4-(1,2,4-oxadiazol-3-yl) aniline and 1-hydroxybenzotriazole, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and reaction liquid B is 1.5-6.5 mL / min; the pump-in rate of the mixed solution of hydrogen peroxide and acetonitrile and reaction liquid C is 2.0-8.0 mL / min.
9. The process for the preparation of antiviral drug Amoynivir as claimed in claim 1, wherein, The temperature of the first micro-channel reactor is 5-30℃; the temperature of the second micro-channel reactor is 10-20℃; the temperature of the third micro-channel reactor is 50-70℃; the temperature of the fourth micro-channel reactor is 70-90℃.
10. A process for the preparation of antiviral drug Amoynivir as claimed in claim 1, wherein, The pressure of the first micro-channel reactor is 1.0-3.0 MPa; the pressure of the second micro-channel reactor is 1.0-3.0 MPa; the pressure of the third micro-channel reactor is 1.5-4.0 MPa; the pressure of the fourth micro-channel reactor is 2.0-6.0 MPa.